This invention relates in general to a display panel comprised of a plasma charge transfer device and, in particular, to an arrangement for incorporating a cursor feature into such a panel.
Display panels of the type to which the present invention pertains are well-known in the art. An example of such a display panel is given and described in U.S. Pat. No. 3,781,600, issued to Coleman et al. on Dec. 25, 1973, and entitled "Plasma Charge Transfer Device". This patent is incorporated by reference herein for all that it shows and teaches.
The display panel described in the referenced patent is comprised of an enclosure which is formed by a front and a rear plate with at least the front plate being constructed of a transparent material such as glass. The front and rear plates of the enclosure are maintained in a spaced-apart relationship and are sealed together along their outer perimeters to provide a hollow inner chamber which is divided into a plurality of parallel display channels. These display channels are in turn filled with an ionizable medium such as one of, or a mixture of, neon, argon, helium, kypton, xenon, hydrogen and nitrogen.
Input and erase electrodes are located at opposite ends of each display channel and a plurality of transfer electrodes are alternately disposed on the front and back plates of the panel to intersect each of the display channels. These transfer electrodes are in turn interconnected so that alternate electrodes on the front and rear plates are suitably connected to provide a four phase transfer electrode network. In this way, the transfer electrodes are arranged into four distinct groups with all of the electrodes of a group being interconnected.
By applying a suitable potential between adjacent electrodes on the opposing walls of a display channel, the gas between these two electrodes is ionized causing a light emission or light dot to occur. Through the synchronous application of a suitable voltage potential to the input, transfer and erase electrodes, such light dots can be introduced, shifted and held in place within the display channels of the panel. By combining several such display channels together into a single display panel, it is possible to provide a visual display of numbers, letters or other patterns; to shift the display of such numbers, letters or patterns along the length of the display panel; and to hold the display of such numbers, letters or patterns in place.
When using such a display panel, it is often necessary to highlight or otherwise designate a portion of the material being displayed. One technique for implementing such a feature is to incorporate into the display panel an arrangement for introducing and shifting a cursor line along the length thereof. In implementing such an arrangement, it is desirable to be able to operate the cursor independent of the remainder of the display panel so that a cursor line can be introduced to and shifted along the length of the panel without destroying the material being displayed or having to regenerate the displayed material each time the cursor line is moved.